The eyelid speculum is a well known device in the field of ophthalmology, both for use in diagnostics and in surgery of the anterior and posterior segments of the eye. The purpose of an eyelid speculum is to mechanically retract the eyelids from the surface of the eyeball. Although retraction is necessary for a physician to work, it keeps the eyelids from performing their natural function of lubrication. Therefore, there is a risk of the cornea drying out. Current practice requires an assistant to irrigate the area manually every few moments, so as to provide artificial lubrication to neutralize the drying process caused by the speculum. Long-term non-lubrication of the eye when the speculum is in place may cause injury to the cornea, affecting its transparency and integrity.
There exist speculums with irrigation/aspiration features (Storz Ophthalmic Inc., U.S. and Moria Co., France), however these are provided in a manual form, requiring the physician to push or pull on the plunger of the syringe provided as needed. This is not practical as the physician's hands are required for the surgery and constant removal from the site is counter-productive. Therefore, there is no added benefit to this speculum, as a second set of hands is still necessary to make it useful.
Additionally, the physician working with the speculum requires an illumination source to illuminate the work area. The ophthalmic surgeon operates through use of a microscope with an illumination source which delivers coaxial light. The coaxial light source provides a high level of illumination which has a phototoxic effect on the eye tissue. It is necessary to use a combination of filters or light-dimming techniques to reduce these effects. Even so, the surgeon uses only a portion of the light which reaches the anterior eye tissue and the remaining, unnecessary light penetrates the eye and is absorbed by the retina. The intensity of the unnecessary light causes phototoxicity, damaging the photoreceptors on the retina. Research has shown that not only are the rods and cones affected, but the excess light on the retina may cause bums on the different layers of the retinal tissue. In addition, the intense light is uncomfortable for the patient and may cause excess tearing.
In certain techniques, such as vitrectomny and endo-photocoagulation, for the treatment of advanced retinal disorders, different types of miniature probes are introduced into the eye, by way of example, for cutting membranes, aspiration of residues, oil and gas infusions and laser photocoagulation therapy. Included in these probes is an illumination probe which functions in illuminating that small portion of the retina which is being treated. Consequently, a small portion of the retina receives a concentrated quantity of light delivered by the probe, which is connected to a strong light source. This type of light source also causes the phototoxic effect reported above.
U.S. Pat. No. 5,054,906 to Lyons discloses an indirectly illuminating ophthalmalogical speculum which is primarily suited for external illumination of the cornea in ophthalmogical procedures on the surface of the eye. The speculum is provided as a conventional eyelid speculum with two fiber optics mounted thereon. These fiber optics do not provide a circumferential or constant homogeneous illumination of the eye. Additionally, the Lyons speculum does not provide for trans-illumination of the eyeball, for use in cases where the physician must view the interior of the eye, but rather is designed for use on the surface of the eyeball.
U.S. Pat. Nos. 5,582,608 and 5,695,492 to Brown describe an embodiment with a ring illumination for hand-held use, or to be attached to a support. The device must be used in combination with an eyelid speculum, or the eyelids will occlude the field under observation. Brown provides interior trans-illumination for the purpose of retroillumination, i.e. for the physician to look at the light returning through the lens to see the pathology of the lens. However, the Brown patent does not provide for trans-illumination for the pupose of examining the retinal pathology. Examination of the retina requires a stronger light intensity, potentially causing damage to the retina during long-term radiation. The Brown patent does not allow for this use, or make accommodation for minimizing the damage of a light which is introduced conventionally through the pupil of the eye.
Therefore, it would be desirable to provide an eyelid speculum which would automatically irrigate and aspirate the eye surface, while optionally providing a light source which would provide homogeneous, constant, well-distributed illumination of either the interior or exterior of the eyeball as needed while not causing phototoxic effects on the eye tissue and would provide an illumination system independent of the optical system.